THE EFFECTS OF POPULATION BOTTLENECKS ON MULTILOCUS DNA VARIATION IN ROBINS

The effects of bottlenecks on genetic variation in two wild population s of New Zealand robins (Petroica australis australis) were examined u sing multilocus minisatellite DNA probes, In each case the size and ti ming of the bottlenecks were known, together with the location of the source populations, The two founder events occurred in 1973 and both i nvolved five or fewer individuals, Parameters of multilocus DNA profil e variation, specifically average percent difference (APD), heterozygo sity, numbers of polymorphic loci, and numbers of novel restriction fr agments present, were used to measure levels of minisatellite DNA vari ation in the two sets of source and translocated robin populations, Ne w statistical methods are described that test the significance between the APDs of source and bottlenecked populations, An overall trend tow ard reductions in minisatellite DNA variation through bottleneck event s was observed, However, despite establishment from only one or two fo unding pairs, moderate levels of variation were maintained in both bot tlenecked populations, These results indicate that catastrophic losses of multilocus DNA variation, like single-locus variation, should not be regarded as an inevitable consequence of founder events and populat ion bottlenecks.